What determines thickness
Dimensions, stiffness, weight, bends, fixing method and finish determine the choice. A small enclosure may use 1–1.5 mm sheet; larger panels or loaded brackets often require 2–4 mm or more. These are examples, not design specifications.
Geometry and cost
Folded edges, flanges and ribs can increase stiffness without automatically increasing thickness. Thicker sheet increases material cost, cutting time and bending force.
Send for review
Provide STEP/PDF, overall dimensions, material, visible surfaces, fixing method and loading requirements. We can discuss manufacturing adjustments before production.